1. Field of the Invention
The present invention relates generally to evacuation of a vacuum vessel and, more particularly, to a method and apparatus for evacuation for efficiently discharging hydrogen from a vacuum vessel.
2. Description of the Prior Art
To evacuate a vacuum vessel to the extent of producing a high or ultra-high vacuum, a turbo-molecular pump has been conventionally used. Such type of pumps, however, have a drawback in that they cannot sufficiently discharge light weight gases such as hydrogen from a vacuum vessel since their ability to evacuate light weight gases having a relatively low molecular weight, such as hydrogen is insufficient.